Spectroscope utilizing a coupler to concurrently apply parallel light beams to a sample and a reference light and processing the resulting light beams thereby compensating for environmental changes

Abstract

A spectroscope comprising an optical fiber placed in a light path to a sample chamber, wherein a light beam outputted from the optical fiber is divided into two using an optical coupler, and wherein the two divided light beams are made incident on a measurement optical fiber and a reference optical fiber, respectively, whereby accuracy of measurement of the spectral characteristics of samples is enhanced because the outgoing light is made incident on the measurement and reference optical fibers concurrently when the light to the sample chamber becomes non-uniform due to environmental changes.

What is claimed is: 
     
       1. In a spectroscope comprising a reference path using a first optical fiber comprising an input end and an output end and a measurement path using a second optical fiber comprising an input end and an output end with a sample chamber in said measurement path, the improvement comprising: a third optical fiber comprising an input end and an output end, said input end being located in a light path to said sample chamber;   an optical coupler means connected to said input end of said first optical fiber, said input end of said second fiber and said output end of said third optical fiber and for separating light transmitted through said third optical fiber into two similar light beams for transmission through said first and second optical fibers, respectively, so that light beam transmitted through said second optical fiber is incident on said sample chamber; and   detector means connected to said output end of said first optical fiber and to said output end of said second optical fiber for detecting output light beams from said first and second optical fibers, respectively, wherein said output light beam from said second optical fiber is a measurement light beam resulting from light being incident on said sample chamber, and output light beam from said first optical fiber is a reference light beam, and for processing said measurement light beam and said reference light so as to compensate for environmental changes and/or deterioration of light.   
     
     
       2. The spectroscope of claim 1, wherein said optical coupler means comprises a half mirror. 
     
     
       3. The spectrosocpe of claim 1, wherein said optical coupler means comprises a right angle mirror. 
     
     
       4. The spectroscope of claim 1, wherein said optical coupler means comprises a condensing lens or mirror. 
     
     
       5. The spectroscope of claim 1, wherein said optical coupler means comprises an optical waveguide. 
     
     
       6. The spectroscope of claim 1, wherein said optical coupler means comprises two optical fibers fused or mechanically adhered together in parallel. 
     
     
       7. The spectroscope of claim 1, wherein said optical coupler means comprises a beam splitter, and wherein quantity of light transmitted through said second optical fiber is greater than the quantity of light transmitted through said first optical fiber. 
     
     
       8. The spectroscope of claim 1, wherein said detector means has signal integration times different for signals detected from said first optical fiber and said second optical fiber. 
     
     
       9. A spectroscope comprising: a measurement optical fiber comprising an input end and and output end with a measurement sample disposed therebetween;   a reference optical fiber comprising an input end and an output end;   a light source for generating an output light;   a first optical means for parallizing said output light from said light source and for producing a parallized output light;   a Michelson interferometer to which said parallized output light from said first optical means is made incident and which outputs and output light;   a second optical means for focusing said output light from said Michelson interferometer;   a first optical fiber comprising an input end and an output end, said input end being located in a vicinity of a focal plane of said second optical means and within range of an image of said light soruce made on said focal plane;   an optical coupler means connected to said output end of said first optical fiber, said input end of said reference optical fiber, and said input end of said measurement optical fiber, and for separating outgoing light from said first optical fiber into two similar light beams and for making said two light beams incident on said measurement and reference optical fibers, respectively, with a light beam being incident on said measurement sample in said measurement optical fiber; and   detector means connected to said output end of said reference optical fiber and to said output end of said measurement optical fiber for detecting output light beams from said measurement optical fiber after being incident on said measurement sample and from said reference optical fiber, respectively, and for processing the two output light beams thereby to compensate for environmental changes and/or deterioration in said light source.   
     
     
       10. The spectroscope of claim 9, wherein said optical coupler means comprises a beam splitter, and wherein quatity of light transmitted through said measurement optical fiber is greater than the quantity of light transmitted through said reference optical fiber. 
     
     
       11. The spectroscope of claim 9, wherein said detector means has signal integration times different for signals detected from said reference and measurement optical fibers. 
     
     
       12. A spectroscope comprising: a light source for producing an output light;   a first optical means for parallizing said output light from said light source;   a light processing means for producing an output light;   a second optical means for focusing said output light from said light processing means;   a measurement optical fiber comprising an input end and an end with a measurement sample disposed therebetween;   a reference optical fiber comprising an input end and an output end;   a first optical fiber comprising an input end and an output end, said input end being located in a vicinity of a focal plane of said second optical means and within reange of an image of said light source made on said focal plane;   an optical coupler means connected to said input end of said measurement optical fiber, said input end of said referece optical fiber, and said output end of said first optical fiber, for branching light from said first optical fiber into two similar light beams and for making said two light beams incident on said reference optical fiber and said measurement optical fiber, respectively, with one light beam being incident on said measurement sample in said measurement optical fiber; and   means connected to said output end of said measurement optical fiber and to said output end of said reference optical fiber and for detecting output light beams from said measurement optical fiber and said reference optical fiber and for processing said output light beams so as to compensate for environmental changes and/or deterioration of said light source.   
     
     
       13. The spectroscope of claim 12, wherein said optical coupler means comprises a beam splitter, and wherein quantity of light transmitted through said measurement optical fiber is greater than the quantity of light tranmsitted through said reference optical fiber. 
     
     
       14. The spectroscope of claim 12, wherein said detector means has signal integration times different for signals detected from said reference and measurement optical fibers. 
     
     
       15. The spectroscope of claim 12, wherein said light processing means is one selected from the group consisting of an acousto-optical device, a diffraction grating, and an optical filter. 
     
     
       16. The spectroscope of claim 1, wherein further comprising means for processing signals obtained from said first and second optical fibers by said detector means so as to eliminate adverse effects caused by environmental changes. 
     
     
       17. The spectroscope of claim 9, wherein further comprising means for processing signals obtained from said measurement and reference optical fibers by said detector means so as to eliminate adverse effects caused by environmental changes. 
     
     
       18. The spectroscope of claim 12, wherein furthere comprising means for processing signals obtained from said measurement and reference optical fibers by said detector means so as to eliminate adverse effects caused by environmental changes.